“But we cannot continue to rely on insecure and environmentally unsustainable use of energy,” she said.

The agency estimated in its World Energy Outlook publication that global demand for oil would total 99 million barrels per day in 2035, or 12 mbd more than in 2010, and said that the price could reach $120 per barrel despite current price volatility.

Van der Hoeven said: “The Fukushima nuclear accident, the turmoil in parts of the Middle East and North Africa and a sharp rebound in energy demand in 2010 which pushed CO2 (carbon) emissions to a record high, highlight the urgency and scale of the challenge.”

The IEA said that under its central outlook “scenario”, assuming that governments applied their recent commitments in a “cautious manner”, then what it termed “primary energy demand” would increase by one third between 2010 and 2035, with 90 percent of the growth being generated outside the area covered by the Organisation for Economic Cooperation and Development.

The IEA is the energy policy and research arm of the OECD which acts as a policy forum, and manages strategic stockpiles, for advanced economies.

The emergence of China as the “world’s largest energy consumer” would be consolidated, and China would use 70 percent more energy that the United States by 2035.

But even then, each Chinese person would be consuming less than half the amount of energy used annually by each person in the United States.

On the basis that governments implemented policy changes which they have promised, the percentage of primary energy generated from fossil fuels would fall to 75 percent of the total from 81 percent now.

The proportion of energy generated from renewable sources would increase from 13 percent to 18 percent by 2035, the report said.